Microwavable french fries

ABSTRACT

A microwavable crinkle-cut French fry potato includes deep groves and coatings of oil and encapsulated salt. Crinkle-cut potato pieces are prepared with a solids content of 40-50% by weight, frozen, sprayed with oil and coated with encapsulated salt. A carton for the potato pieces is formed from a single-piece blank provided with a pair of microwave susceptor surfaces and reinforced corners. A removable lid contacts the potato pieces during microwave reconstitution.

FIELD OF THE INVENTION

This invention generally concerns potato pieces that can bereconstituted through use of microwave energy as well as a microwaveinteractive package therefor. More particularly, the invention concernscrinkle-cut French fry potato pieces specially processed so as to beuniquely adapted for reconstitution with microwave energy. Further, theinvention concerns a special carton have microwave susceptor insertswhich contact the potato pieces while restricting steam egress.

DESCRIPTION OF THE RELATED ART

Processing of potatoes for reconstitution by consumers and institutionsas French fries has been known for many years. Likewise, various formsof packaging for such French fries has also been known for a long time.Also, reconstitution of frozen French fries by baking, deep frying inoil, exposure to microwave radiation, and other heating processes arealso known.

According to U.S. Pat. No. 5,310,977 issued to Stenkamp et al., Ore-Ida®has used a paperboard box measuring 5.375 inches by 4 inches by 1.375inches to package crinkle-cut potatoes. Stenkamp et al. proposed the useof microwave susceptor material placed between layers of crinkle-cutFrench fries, where the microwave susceptor material has been configuredwith angular pleats, sinusoidal undulations, or an array of pyramids.Such arrangements complicate the packaging process as they requirecareful layering of the product and the microwave susceptor materials.

According to U.S. Pat. No. 4,931,296 issued to Shanbhag et al., potatogranule coated French fries are known, which may be crinkle-cut, wherefinely ground salt is applied at a concentration of 0.5 to 1.5% byweight to provide an acceptable taste. Shanbhag et al. hypothesize thattheir thin coating on the potato strip forms inhibits steam generated inthe potato during heating from escaping during finish frying so that aninvisible gap is formed between the coating and the product interior.

In U.S. Pat. No. 4,935,592, Oppenheimer discloses a microwave cookingcontainer for browning potato products. The container includes amicrowave susceptor insert having a plurality of longitudinal slotssized and arranged to receive individual French fry potato pieces.

U.S. Pat. No. 5,000,970 issued to Shanbhag et al. concerns a process forpreparing reheatable French fried potatoes. After finish frying, thepotato strips are sprinkled with finely ground salt in an amount of 0.25to about 1.0 percent by weight. Specifically, fat-encapsulated saltgranules may be used.

U.S. Pat. No. 5,049,710 issued to Prosise et al. discloses a package forfood items such as French fried potato strips that are uniform in sizeand shape. The package is arranged such that each of three layers offood items contact microwave susceptor material on two opposite sides.The package includes vent panels that are open during microwave heatingof the food items. Another vented microwave heating package forelongated food products, such as French fries, is disclosed by U.S. Pat.No. 5,096,723 issued to Turpin. The Turpin package has an internal traycomponent. Further, U.S. Pat. No. 5,175,404 issued to Andreas et al.discloses a vented package having microwave receptive heating sheetsarranged so that individual elongated food sticks are heated on at leastthree sides.

The known packages for microwavable French fries generally requirespecial arrangements of the potato pieces. For example, the containersdiscussed above require that the potato pieces be aligned parallel withone another in susceptor packages to have the necessary contact withmicrowave susceptor surfaces. In processing of French fried potatoes,and in the packaging thereof, the potato pieces are normally randomlyoriented. Thus, those packaging arrangements necessitating specialorientation of the potato pieces also require additional handlingequipment which adds processing expense.

BACKGROUND OF THE INVENTION

There continues to be a need in the industry for a microwavable Frenchfry potato product that exhibits a uniformly crisp surface texture, auniformly moist tender interior texture, and a flavor comparable torestaurant fries after reconstitution by microwave heating. Knownprocesses for making French fry potato pieces have not satisfied thatneed as shown, for example, by the prior art patents discussed above.

Moreover, there continues to be a need in the industry for a packagingsystem that accepts French fried potato pieces with a random orientationfor storage, sale, and ultimate reconstitution by the consumer.

SUMMARY OF THE INVENTION

In accord with one broad aspect of the invention, a crinkle-cut Frenchfried potato piece includes longitudinal surfaces having rounded peaksseparated by rounded grooves where the depth of the grooves is about 50%greater than the depth of conventional crinkle-cut French fried potatopieces. Preferably, the deeper grooves have a depth selected so that atleast about 50% of the volume of the potato piece includes the ridgeportion of the crinkle-cut French fries, whereas less than 50% of thevolume of the potato piece occupies the solid core of the crinkle-cutpotato piece.

Consistent with another broad aspect of the invention, a process forpreparing potato pieces for microwave reconstitution includes makingpotato pieces having a relatively high total solid content, coatingfrozen potato pieces with soybean oil, and applying encapsulated salt.Use of encapsulated salt enhances the microwave reconstitution of thepotato pieces since encapsulation maintains integrity of the salt sothat it can function as a dielectric during the microwave heatingprocess.

Another broad aspect of the invention concerns a specialized packageadapted to receive randomly position French fry potato pieces. Thepackage includes microwave susceptor material positioned on the insideof the two major surfaces. In use, one major surface of the package isremoved, the potato pieces are aligned so as to be one layer thick, thelid is pressed into contact with the potato pieces, and the preparedpackage subjected to microwave heating.

Other more detailed aspects of the crinkle-cut potato pieces, theprocess for preparing those pieces, the package, as well as the processof reconstituting French fried potatoes using that package are describedin more detail in the specification below.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Many objects and advantages of this invention will be apparent to thoseskilled in the art when this specification is read in conjunction withthe attached drawings wherein like reference numerals have been appliedto like elements and wherein:

FIG. 1 is a perspective view of a typical elongated potato piece;

FIG. 2 is an enlarged, partial cross-sectional view taken along the line2-2 of FIG. 1;

FIG. 3 is a further enlarged, cross-sectional view of a portion of thesurface of the potato of FIG. 2;

FIG. 4 is an enlarged, cross-sectional view of a corresponding portionof the surface of a prior art potato piece;

FIG. 5 is a flow diagram of the process steps involved in making amicrowavable potato piece according to this invention;

FIG. 6 is a plan view of a carton blank prior to forming, according tothis invention;

FIG. 7 is an isometric view of a completed package according to thisinvention;

FIG. 8 is an isometric view of an opened package according to thisinvention; and

FIG. 9 is an isometric view of an opened package according to thisinvention prepared for microwave heating.

DETAILED DESCRIPTION OF THE INVENTION

Turning to FIG. 1, an elongated potato piece 20 in accord with thisinvention is generally illustrated. The potato piece is generallyelongated and generally square in cross section. Typical cross-sectionaldimensions of the finished potato piece are ⅜ inch by ⅜ inch to ½ inchby ½ inch. Those typical dimensions of the finished piece are, however,somewhat smaller that the typical dimensions of the raw, pre-processing,potato piece. For example, the finished potato piece may by ½ inch by ½inch while the same potato piece started with 9/16 inch by 9/16 inchdimensions when raw. The length of a typical potato piece lies in therange of 1½ to 5 inches. Potato pieces with these typical dimensions areknown as French fries.

While the surface of the potato pieces may be generally smooth asillustrated in FIG. 1, the surface may have any other knownconfiguration. The preferred configuration for microwavable French friesaccording to this invention, however, is commonly known as crinkle-cut.For example, in FIG. 2, the longitudinally extending surfaces 22, 24 ofthe potato piece have undulations which may be smooth as illustrated.The undulations of each surface define a plurality of peaks 26, witheach adjacent pair of peaks 26 being separated by groove 28. Thepeak-to-peak distance, p, between crests of the undulations preferablyremains constant. On the actual surface of the crinkle-cut French fry,those peaks 26 are ridges that extend transversely to the longitudinalaxis of the French fry potato piece. Ideally, those ridges areperpendicular to the longitudinal axis of the French fry, but during thecutting process, the ridges do not always form in a perpendicularrelationship to that axis. Accordingly, due to the manner thecrinkle-cut surfaces are formed, the grooves and crests on any givensurface, while parallel to one another, may extend at an angle otherthan 90° to the longitudinal axis.

To further define the surface of the crinkle-cut French fry potatopieces, that peak-to-peak distance, p, or the ridge-to-ridge distance,is measured perpendicularly to the parallelly extending ridges.Moreover, the grooves 28 between the ridges 26, are parallel to theridges 26 and extend transversely to the longitudinal axis of the potatopiece.

As seen in FIG. 2, the grooves between adjacent ridges of thecrinkle-cut potato piece have a depth, A. The crinkle-cut potato piecethus has ridges 26 on each side and a solid core, c, which is notpenetrated by the grooves 28. The depth, A, of the grooves 28 is thesame as the height of the ridges and is a very important feature of thepresent invention. More particularly, the depth, A, of the grooves isselected to be about 50% greater than the corresponding depth ofconventional crinkle-cut potato pieces. In the past, the depth of thegrooves was typically about 1/16 inch. However, according to thisinvention, the depth, A, of the grooves is in the range of 0.08 to 0.11inches, preferably about 0.094 or 3/32 inch.

The curved features of the grooves and the ridges, when viewed in crosssection, is another important feature of the invention. Morespecifically, the curved or rounded shape of the bottom of the grooves26 exposes more of the core of the potato piece to processing. That is,the distance to the surface of the potato piece is shorter with thedeeper, curved grooves than in prior known potato pieces. That distancehas important effects on process steps used to prepare potato pieces formicrowave reconstitution.

FIGS. 3-4 illustrate the differences between crinkle-cut potato piecesof this invention and the prior art. FIG. 3 is a further enlarged crosssection of a potato piece, similar to the view of FIG. 2. FIG. 4, is anenlarged view of a prior art crinkle-cut potato piece, with the samescale as FIG. 3. In FIG. 4, the depth, B, of the grooves 32 wastypically about 1/16 inch for commercial potato pieces. Another priorart surface treatment (not illustrated) is known in the art as aconcertina cut and is characterized by peaks separated by deep grooves,where the peaks on one side of the potato piece are directly oppositecorresponding peaks on the opposite side of the potato piece. In thatrespect, the concertina cut is different from the crinkle-cut becausethe peaks on one side of the crinkle-cut potato piece are directlyopposite corresponding grooves on the opposite side of the potato piece.

In accord with the present invention, the depth, A, of the groove isselected to be about 50% larger than the depth, B, of the prior artcrinkle-cut potato piece. In the context of a ½ by ½ inch French friedpotato piece, that 1/16 inch depth, B, resulted in 60% of the potatopiece being in the core region while about 40% of the potato piece wasin the ridges. With the deeper grooves of the present invention (i.e.,with the depth, A), the ridges contain 49-63% of the potato-piecevolume, whereas the solid core contains 37-51% of the potato-piecevolume. After processing and reconstitution by microwave heating, it hasbeen determined that the deeper grooves (or higher ridges) of thepresent invention give the fries more surface area where the solids ofthe potato are concentrated and this higher surface area will deliver acrisp exterior and while the smaller core of the fry provides the moistpotato interior characteristic of a deep-fried French fry.

We turn now to the process for preparing the potato pieces, see FIG. 5.Initially, the potatoes are washed and peeled, 100, using standardconventional processing procedures. Next, the potatoes are cut intoelongated pieces, 110. Those elongated pieces typically have a generallysquare cross section. In the cutting step 110, the cutting process maygive smooth surfaces, crinkle-cut surfaces, or concertina cut surfacessince the process of this invention yields improved microwavereconstitution for any surface configuration. Nevertheless, thepreferred surface configuration for the cutting step 100 is acrinkle-cut with the deeper grooves for each longitudinal surface of thepotato piece. The knives used for the crinkle-cutting step are selectedand designed such that the knives cut grooves with a depth of about 0.08to 0.110 inch, i.e., about 50% deeper than conventional crinkle-cutpotato pieces. As a result, the volume of the core may be less thanabout 50% of the volume for the potato piece.

The potato pieces are then processed, 120, until the resulting pieceshave a 40% to 45% total solid content, preferably about 42.5%. Thischaracteristic of the potato piece is sharply contrasted to, and about33% greater than, the nominal solid content of conventional potatopieces, which is about 31%. These solid content values are weightpercentages and are preferably determined using standard chemicalanalysis techniques—specifically the AOAC vacuum oven method.

The step of processing the potato pieces to about 42.5% total solids 120involves several intermediate steps. In particular, the cut potatopieces are blanched 122 following standard conventional processingprocedures. The blanched potato pieces are dried 124 to effect a weightloss of 10-15% by weight. Preferably the drying step occurs in a forcedair dryer at a temperature in the range of 100° to 180° F.

After drying, the potato pieces are parfried 124 in hot oil until thetotal solids are concentrated to the range of 27% to 30% total solids.Preferably, the oil temperature lies in the range of 330° to 360° F.Following that parfry step 124, the potato pieces are equilibrated 128at ambient temperature for a period of 30 to 60 seconds.

Then, the equilibrated potato pieces are subjected to a second parfrystep 129. In the second parfry step 129, the total solid content of thepotato pieces is concentrated to 40 to 45%, preferably about 42.5%. Thesecond parfry step 129 is also conducted using hot oil, but at a highertemperature than that of the first parfry step. Specifically, the secondparfry step 129 uses oil at 375° to 395° F.

After processing to the 40% to 45% total solid content, the potatopieces are frozen in a conventional manner 130. For example, a spiralfreezer or any other conventional freezing apparatus may be used.

Next, the frozen potato pieces are coated with oil, 140. To effect theoil coating, the potato pieces are conveyed through a drum with finsthat tumble 142 the potato pieces. As the potato pieces are tumbling,soybean oil is sprayed 144 onto the surface of the potato pieces so thatthe oil constitutes about 1% by weight of the potato piece. The oil ispreferably applied to the entire surface area of each potato piece. Tobe suitable for subsequent processing steps, the oil must be liquid attemperatures of 50° F. or more and must become solid at 32° F. Oil whichsolidifies at higher temperatures solidifies too quickly on the frozenpotato pieces.

Then, the potato pieces are coated with salt 150 so that the saltrepresents 0.80% to 1.5% by weight of the potato piece, preferably about1.25%. The quantity of salt on the potato pieces is determined using aCorning Chloride meter and the Corning Analytical Method. Encapsulatedsalt is used. The soybean oil coating functions as a tacking agent forthe encapsulated salt and the oil must remain tacky long enough that thesalt can adhere before the oil solidifies. It has been determined thatsalt brine and regular salt cannot be substituted for encapsulated saltin this invention. In particular, salt brine has been found to pullwater out of the potato pieces. Similarly, regular salt pulls water outof the potato pieces. Encapsulated salt, on the other hand, does not actto pull water out of the potato pieces. Furthermore, since salt is adielectric, and since encapsulation causes the salt to retain itscrystalline form, during the microwave reconstitution of these potatopieces, the dielectric character of salt causes it to heat the surfaceof the potato pieces and make it crisp. As a result, the combination ofoil and encapsulated salt improves the tender crispness of the resultingproduct.

When the potato pieces have been coated with encapsulated salt, thepotato pieces are packaged, 160, and transferred to freezers for storage170.

The carton used for the product is also a part of the invention. Moreparticularly, the preferred package comprises the carton filled with afoodstuff and is sized to fit in conventional microwave ovens having aturntable. The preferred foodstuff here comprises microwavablecrinkle-cut French fry potato pieces prepared as described above.Package depth is selected such that the package will stand on its sideon a typical freezer shelf in an upright freezer case of a grocerystore. In addition, the package depth must be sufficient that it can beeasily filled and sealed using mechanical carton-forming equipment.Based upon those considerations, it has been found that a suitablecarton is 7.25 inch square by 1.25 inch high.

Turning now to FIG. 6, the preferred package includes a cartonfabricated from a paperboard blank 200. The paperboard itself may be 18point (0.018 inch) solid bleached sulfate (SBS) paperboard having 48gauge (0.00048 inch) metalized oriented polyester (OPET) adhesivelaminated to the interior surface and being clay coated on the outsidesurfaces to enhance printability. The carton blank 200 includes twomajor surfaces 202, 204 which are generally square, the surface 202eventually becomes the bottom of the carton while the surface 204eventually becomes the top of the carton.

Integrally attached to two side edges of the first major surface 202 area pair of inner side panels 206, 208. A locking slot 216 is provided ateach end of each inner side panel 206, 208. Integrally attached to theother two side edges of the first major surface 202 are an inner frontpanel 210 and a back panel 212. Each end of both the inner front panel210 and the back panel 212 includes a laterally extending locking tab214 having a hook 215 designed to cooperate with the slot 216 of theadjacent inner side panel 206, 208. The locking tab 214, the hook 215,and the slot 216 comprise a mechanical attachment means operable to holdthe adjacent panels together. Cooperation between the hook 215 and theassociated slot 216 helps establish a rigid corner for the resultingcarton.

The second major surface 204 of the blank 200 is integrally connectedalong one side to the back panel 212 so that the two major surfaces 202,204 are aligned with one another. Integrally attached to parallel sidesof the second major panel 204 are a pair of outer side panels 218, 220.Each outer side panel 218, 200 is longitudinally aligned with acorresponding one of the inner side panels 206, 208. Integrally attachedto the remaining side of the second major surface 204 is an outer frontpanel 230. That front panel 230 is scored at 232, 234 to define alifting tab 238. Moreover, the front panel 230 is notched 236 at twoplaces to provide easy access to the lifting tab 238 for removal.Suitable conventional scoring and creasing is used to define folds(shown as broken lines) in the blank 200 so that carton formingmachinery can form an open tray and, when the tray is filled with potatopieces, close and seal the top.

The inner surface of the blank 200 also includes two microwave susceptorsurfaces 240, 242. The first susceptor surface 240 is attached to thefirst major surface 202 and is square, with dimensions sufficient tosubstantially cover the first major surface 202 while leaving a space ofabout ⅛ inch between the perimeter of the first susceptor surface 240and the perimeter of the first major surface 202. To properly heat thepotato pieces, the first susceptor surface 240 should be substantiallycoextensive with the first major surface 202. While a ⅛ inch distancebetween the respective perimeters meets the condition of substantialcoextensivity, distances greater than ⅛ inch can also be accommodated aslong as the products to be heated will have substantial surface contactwith the susceptor material.

The second susceptor surface 242 is attached to the second major surface204 and is generally square but includes chamfered corners. Theperimeter of the second susceptor surface 242 is configured and sized tobe slightly inside the score line 244, 246 along which the inside of thesecond major panel 204 can be opened. Again, a distance of about ⅛ inchfrom that score line, and from the hinge line with the back panel 212provides substantial coextensivity between the second susceptor surface242 and a removable portion of the second major surface 204.

To assemble the package, the inner side panels 206, 208, the inner frontpanel 210, and the rear panel 212 are folded relative to the first majorsurface 202 so that the first susceptor surface 240 is located at thebottom. The projections 215 are attached to the respective slots 216 sothat a self supporting tray is formed with an integral lid. The cartonis then filled with a predetermined weight of product. In the case ofthis invention the preferred product is potato pieces, and inparticular, crinkle-cut French fried potato pieces having the deepgrooves described above. One advantage of the open tray of the cartonhere is that the potato pieces can be deposited randomly into the tray.With the depth of the tray being on the order of 1.25 inches, when thepotato pieces are deposited some can be on top of others withoutadversely affecting the ability to close the carton to form the package.

The filled package is subsequently closed and sealed. In particular, thesecond major surface 204 is folded along the hinge formed between it andthe rear panel 212 into position overlying the tray. Thereafter, theouter side panels 218, 220 are sealed to the corresponding inner sidepanels 206, 208 and the outer front panel 230 is sealed to the innerfront panel 210. The completed package is illustrated in FIG. 7.

It should be noted that the completed package has score lines 246′, 244′extending from the notches on the outer front panel 230 around thelifting tab 238, along edges between the second major surface 204 andthe outer side panels 218, 220 (not visible), such that a generallytriangular gusset is defined at each corner of the carton on the topsurface of the carton. Moreover, in the preferred arrangement, the scorelines 244, 246 (see FIG. 6) on the inside of the second major surface204, are laterally offset from the score lines 244′ 246′ (see FIG. 7) onthe outside of the second major surface 204. That offset allows deep,substantially continuous score lines to be used on both sides of thesurface 204 while maintaining a seal for the product. During opening,the paper board fails between the offset score lines to leave thinner,flexible edges on the top 204.

To prepare the package for reconstitution of the product, the consumermust lift the top from the carton. To do so, the lifting tab 238 ispulled out and up. The notches 236 facilitate this step. Next, thesecond major surface 204 is peeled back along the score lines 246′, 244′so that a gusset 250, 252, 254, 256 remains at each corner. (See FIG.8). These gussets stiffen the corners of the remaining tray and helpkeep the side walls stiff. Furthermore, the gussets help keep the cartonsides from springing outwardly during microwave reconstitution. Then thesecond major surface 204 is separated from the rear panel 212 along thehinge line there between.

The product is then arranged by the consumer in the tray so that asingle layer of product rests on the first susceptor surface 240. Thesingle layer of product has a substantially uniform depth which isconsiderably less than the depth of the tray.

Next, see FIG. 9, the consumer replaces the upper major surface 204 ontop of the tray such that the second susceptor surface faces theproduct. The top is then pressed down into the tray until the secondsusceptor surface contacts the product. That is, the product issandwiched between the two susceptor surfaces and has contact with bothsurfaces. The first major surface 205 is frictionally held in positioncontacting the product by the sides of the carton. In addition, agenerally triangular vent opening 260 is defined at each corner of thelid, between the lid and the adjacent walls.

Reconstitution 180 of the frozen potato pieces, prepared in accord withthis invention, is accomplished by placing the package of FIG. 9, in amicrowave oven. During microwave heating, steam is generally trappedinside the package until it reaches the generally triangular ventopenings 260 at the corners. By virtue of contact with the microwavesusceptor surfaces, the individual potato pieces are browned andrendered crispy on the exterior, while the steam heats the interior andkeeps the interior moist. Without the gussets, the carton sides are freeto spring out, thereby allowing the top, i.e., the second major surface204, to be lifted up off the fries. If the top is spaced above thepotato pieces by a distance exceeding about 5 mm, the product is notproperly crisped by the upper susceptor surface. The length of timerequired for microwave reconstitution depends on the foodstuff in thepackage and the amount of that foodstuff which is present. By way ofexample, where the foodstuff in the package comprises crinkle-cutmicrowavable French fry potato pieces according to this invention, whereabout 4.75 ounces are present, the French fries are reconstituted whenmicrowaved for about 4 minutes using a microwave oven rated at an outputof about 1000 watts. Larger quantities require longer heating timeswhile smaller quantities need shorter heating times.

For access to the heated product, the consumer grasps the portion of thelifting tab 238 which extends above the inner front panel 210, liftsthat tab 238 and removes the top 204 to expose the hot product. Wherecrinkle-cut potato pieces are used, the resulting potato pieces arecomparable to restaurant prepared, oil-fried, French fried potatoes.This result is accomplished because the high solid content in the largerridge portion of the crinkle-cut pieces causes the ridges to be wellheated through contact with the susceptor surfaces.

It should now be apparent to those skilled in the art that thisinvention has describes a new microwavable French fried potato product,an improved package for microwave reconstitution of frozen French friedpotato products, an improved process for preparing those frozen Frenchfried potato products, as well as a new method for reconstitution ofthose products. Nevertheless, this specification is intended to beillustrative, and not limiting, as it will be apparent to those skilledin the art that many substitutions, variations, and equivalents existfor the features which have been described. Accordingly, the full scopeof this invention is defined by the appended claims including all legalequivalents to the elements and features set forth therein.

1. A potato piece comprising: an elongated potato piece having agenerally square cross section, a generally longitudinal axis, andlongitudinally extending sides; each longitudinally extending sidehaving a plurality of ridges separated by grooves, the ridges andgrooves oriented generally transverse to the longitudinal axis, andcooperating to define a core portion; the ridges being rounded in crosssection; the grooves being rounded in cross section; where the potatopiece includes an oil coating comprising 1% by weight; and where thepotato piece includes a coating of encapsulated salt in amount in therange of 0.8 to 1.5% by weight.
 2. The potato piece of claim 1 whereinthe oil is solid at temperatures below 32° F. and is liquid attemperatures above 50° F.
 3. The potato piece of claim 2 wherein the oilis soybean oil.
 4. The potato piece of claim 1 having a solid content inthe range of 40 to 50% by weight.